Model Analysis

Structural Equation Modeling with lavaan in R

Erin Buchanan

Professor

Model Terms

Degrees of Freedom (df)
- Determined by the number of manifest variables and estimated values
- df = Possible Values - Estimated Values
- Possible Values = Manifest Variables * (Manifest Variables + 1) / 2
Identification
- Include at least three manifest variables
- Create models with df > 0
- Use scaling and constraints to control df

Analyze the Model

#model specification
visual.model <- 'visual =~ x1 + x2 + x3 + x7 + x8 + x9'

#model analysis
visual.fit <- cfa(model = visual.model,
                  data = HolzingerSwineford1939)

Visual Speed Model

Summarize the Results Overall

summary(visual.fit)

lavaan (0.5-23.1097) converged normally after  27 iterations

  Number of observations                           301

  Estimator                                         ML
  Minimum Function Test Statistic              106.553
  Degrees of freedom                                 9
  P-value (Chi-square)                           0.000

Parameter Estimates:

Summarize the Results Loadings

Latent Variables:
                   Estimate  Std.Err  z-value  P(>|z|)
  visual =~                                           
    x1                1.000                           
    x2                0.586    0.139    4.215    0.000
    x3                0.882    0.149    5.923    0.000
    x7                0.728    0.137    5.320    0.000
    x8                0.944    0.143    6.599    0.000
    x9                1.205    0.170    7.095    0.000

Summarize the Results Variances

Variances:
                   Estimate  Std.Err  z-value  P(>|z|)
   .x1                0.973    0.093   10.405    0.000
   .x2                1.249    0.106   11.789    0.000
   .x3                0.975    0.090   10.842    0.000
   .x7                0.979    0.087   11.311    0.000
   .x8                0.678    0.069    9.841    0.000
   .x9                0.455    0.069    6.580    0.000
    visual            0.386    0.092    4.201    0.000

Let's practice!

Structural Equation Modeling with lavaan in R